Answer:
Initially, the ballast tanks are filled with water. The weight of the submarine is equal to the upthrust of the water at the position of the submarine under water. When high pressure air is released into the ballast tanks displacing the water, the weight of the submarine becomes less than the upthrust of the water thus the net force is is upwards and it forces the sub to resurface. This is according to the Archimedes principle which states that a a body partially or wholly immersed in water displaces its own weight of the fluid in which it is immersed.
It would be B because you want to know which TEMPERATURE is the best for the plant. Different brightness for a bulb will give different amounts of heat. Since the amount of heat is your INDEPENDENT VARIABLE, you have to change the amount of heat for each plant, so the brightness of bulbs. Therefore, B is your answer!
Why would you ask a question if you didnt have a question?
Just get someone to report it, and itll be deleted
Ba stays as Ba+2 and Cl stays as Cl-